Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for Seven Sisters: 08-29 (97), 08-30 (96), 08-28 (95), 08-31 (93), 08-27 (92) — by astronomy; check the weather when the night is within four days.

2028-08-15astronomy score per night — click a bar for that night2028-09-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2028-08-15 Tue	46	—	unknown	02:35–04:50 (good, 2.25 h)	72.5° 07:30	6.67	26%	23.2°
2028-08-16 Wed	57	—	unknown	02:20–04:50 (good, 2.5 h)	72.5° 07:25	6.73	16%	36.9°
2028-08-17 Thu	64	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.79	9%	51.1°
2028-08-18 Fri	71	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:15	6.84	3%	65.7°
2028-08-19 Sat	73	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:15	6.9	0%	80.6°
2028-08-20 Sun	76	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.96	0%	95.8°
2028-08-21 Mon	78	—	unknown	02:00–04:55 (good, 2.92 h)	72.5° 07:05	7.02	4%	110.9°
2028-08-22 Tue	81	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.07	9%	126.0°
2028-08-23 Wed	83	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.13	17%	140.8°
2028-08-24 Thu	86	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.19	27%	155.2°
2028-08-25 Fri	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:50	7.25	38%	169.2°
2028-08-26 Sat	91	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:45	7.3	49%	177.2°
2028-08-27 Sun	92	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:40	7.36	59%	164.0°
2028-08-28 Mon	95	—	unknown	01:30–05:05 (good, 3.58 h)	72.5° 06:40	7.42	69%	151.2°
2028-08-29 Tue	97	—	unknown	01:35–05:10 (good, 3.58 h)	72.5° 06:35	7.47	78%	138.6°
2028-08-30 Wed	96	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:30	7.53	86%	126.3°
2028-08-31 Thu	93	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:25	7.58	92%	114.1°
2028-09-01 Fri	88	—	unknown	01:35–05:15 (good, 3.67 h)	72.5° 06:20	7.64	96%	102.1°
2028-09-02 Sat	62	—	unknown	02:15–05:15 (good, 3.0 h)	72.5° 06:20	7.7	99%	90.1°
2028-09-03 Sun	48	—	unknown	03:25–05:15 (good, 1.83 h)	72.5° 06:15	7.75	100%	78.3°
2028-09-04 Mon	36	—	unknown	01:00–05:15 (marginal, 4.25 h)	72.5° 06:10	7.81	99%	66.4°
2028-09-05 Tue	27	—	unknown	01:05–05:20 (marginal, 4.25 h)	72.5° 06:05	7.86	96%	54.6°
2028-09-06 Wed	20	—	unknown	01:10–05:20 (marginal, 4.17 h)	72.5° 06:00	7.92	92%	42.8°
2028-09-07 Thu	16	—	unknown	01:10–05:20 (marginal, 4.17 h)	72.5° 06:00	7.97	86%	30.8°
2028-09-08 Fri	20	—	unknown	00:50–05:20 (marginal, 4.5 h)	72.5° 05:55	8.03	79%	18.8°
2028-09-09 Sat	28	—	unknown	00:30–05:25 (marginal, 4.92 h)	72.5° 05:50	8.08	71%	6.5°
2028-09-10 Sun	40	—	unknown	00:20–05:25 (marginal, 5.08 h)	72.5° 05:45	8.13	61%	5.9°
2028-09-11 Mon	55	—	unknown	01:20–05:25 (good, 4.08 h)	72.5° 05:45	8.19	51%	18.7°
2028-09-12 Tue	74	—	unknown	00:50–05:25 (good, 4.58 h)	72.5° 05:40	8.24	41%	31.9°
2028-09-13 Wed	86	—	unknown	00:30–05:30 (good, 5.0 h)	72.5° 05:35	8.29	30%	45.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2028-08-15&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.